Cloning With Not-So-Fresh Cells
Ever since researchers in Scotland electrified the world by cloning Dolly the sheep, scientists have been trying to make cloning a more efficient, useful process. The hope is that cloning can enable researchers to develop better animal models to study human diseases and allow livestock breeders to engineer genetically identical farm animals with desired traits.
Now, researchers in Connecticut and Japan have cloned six calves using cells taken from the ear of a prize bull in Japan that were kept alive in the laboratory for three months before they were used for cloning.
The advance, which will be described in an upcoming issue of the Proceedings of the National Academy of Sciences, could allow scientists to breed animals with specific genetic traits because they could use cells that they had kept in the laboratory long enough to add desired genes. Previously, cloning has used fresh cells.
In an editorial accompanying the study, Mario R. Capecchi of the University of Utah School of Medicine said that while the main applications of the work are for animal breeding, it could make human cloning more feasible.
"Personally, I would not be particularly concerned if a very wealthy, eccentric individual desired to produce a clone of him or herself," Capecchi wrote. "If the intent were to reproduce an exact copy, the wealthy cloner would very likely be disappointed with the results. We have lived with genetic clones, identical twins, for as long as the human race existed."
Solving Sea Lion Deaths
Marine biologists think they've solved a mystery: what killed hundreds of sea lions off the coast of California in 1998.
More than 400 sea lions died along the California coast in the spring of 1998, and Christopher Scholin of the Monterey Bay Aquarium Research Institute and colleagues conducted a variety of tests at the time to try to figure out what happened.
An alga known as Pseudo-nitzschia australis bloomed at the same time of the deaths in the Monterey Bay, producing a potent neurotoxin known as domoic acid, the researchers report in the Jan. 6 issue of Nature. The toxin, in turn, was found in anchovies in the bay, which the sea lions apparently ingested, the researchers said. Traces of the toxin were found in the sea lions, and their brains showed damage consistent with exposure to the substance, the researchers said.
Seeing Rain in the Stars
For generations, farmers in the drought-prone Peruvian and Bolivian Andes Mountains in South America have watched the Pleiades constellation in June to forecast how much rain they could expect in the growing season. The brighter the stars, the more likely there would be rain from October to May, they believed.
Researchers from the University of California at Davis and the Lamont-Doherty Earth Observatory of Columbia University in Palisades, N.Y., decided to study this traditional meteorological method to see if it has a scientific basis.
When wispy clouds high in the atmosphere make it difficult to see the Pleiades in June, that indicates the El Nino weather phenomenon, which comes every two to seven years, is occurring, the researchers found. Rainfall records show that means there probably will be less rain during the growing season and several months afterward.
"Our results suggest that this centuries-old method of seasonal rainfall forecasting may be based on a simple indicator of El Nino variability," the researchers wrote in the Jan. 6 issue of the journal Nature.
The Chimp Has Your Number
Humans can easily memorize strings of numerals up to seven digits long, but they have a hard time with anything much longer. Researchers in Japan have now determined the equivalent for chimpanzees.
Scientists at Kyoto University had previously taught a female chimpanzee named Ai how to use Arabic numerals to represent numbers. She could count from zero to nine by touching the appropriate number on a touch-sensitive computer screen.
In a new experiment, researchers Nabuyuki Kawai and Tetsuro Matsuzawa showed that Ai can remember the correct sequence of any five numbers selected from zero to nine. In series of tests, the researchers showed that Ai scored more than 90 percent correct in memorizing four numbers and about 65 percent with five numbers.
"Ai's performance shows that chimpanzees can remember the sequence of at least five numbers, the same as (or even more than) preschool children," the researchers wrote in the Jan. 6 issue of Nature.
Fooled by a Full Moon
A father and son team of researchers think they have figured out why a full moon looks bigger when it's near the horizon than when it's overhead.
Lloyd Kaufman, a professor of psychology at Long Island University in Brookville, N.Y., and his son, James Kaufman, a researcher with IBM's Almaden Research Center in San Jose, Calif., projected artificial moons onto the sky using special optics and asked volunteers to judge the size from a hilltop on Long Island in New York.
Based on their findings, the Kaufmans propose that when the moon is on the horizon, the brain apparently picks up distant cues from the surrounding terrain and interprets the moon as being farther away. This makes the brain perceive the moon as larger. When the moon is overhead in empty sky, in contrast, there are no distance cues and the moon seems closer and therefore smaller, the researchers said in the Jan. 4 issue of the Proceedings of the National Academy of Sciences.